Miner&#39;s electric safety-lamp



T. STRETTON'. MINERS ELECTRIC SAFETY LAMP. APPLICATION FILED MAYIO, 1920.

Inventor .gm

.lttorneyoairsa states smear crrica THEODORE STRETTON, OF CARDIFF, WALES, ASSIGNOR TO HASLAM & STRETTON' LIMITED, OF CARDIFF,

MINERS ELECTRIC SAFETYLAMF.

Specification of Letters Patent.

Patented Apr.- 1921.

Application filed May 10, 1920. Serial No. 380,254.

To all whom it may com'em:

Be it known that I, THEODORE S'rnE'r'roN,

-- 2. subject of the King of Great Britain and Ireland, residing at 11 Windsor Place, Cardifl", Wales have invented certain new and useful improvements Relating to Miners Electric Safety-Lamps, of which .the following is a specification. V

This invention relates to miners electric safetylamps in which spring contact plugs are mounted on the contact plate carried on the upper part of the lamp, andin which screws are used for securing to the contacts accompanying drawing in which-,-

the hollow cylindrical members b which the spring pressed plugsarecarrie Theinvention consists of a construction comprising the following elements: a con-' tact plate of 'insulatin material, two contacts mounted in said p ate and havin their respective upper and lower faces flus with the respective upper and lower faces of the contact plate, hollow cylindrical members internally screw threaded at their upper ends for connection with the respective contacts on the under face thereof by means of countersunk screws whose top faces are flush with the respective faces of the contacts, and spring pressed plugs at the lower ends of the said cylindrical members as hereinafter described.

The invention comprises the construction hereinafter described withreference to the Figure l is a sectional elevation of the upper part of the lamp,

Fig. 2 is an under plan corresponding thereto. v

Fig. 3 is a sectional elevation showing the upper part of the cell adapted for use when the top of the lamp is constructed according to Fig. l. Fig. 4 is a plan corresponding to Fig. 3. ,In carrying the invention into efiect ac cording to one construction such as thatdescribed in the specification of. a co-pending application, Serial Number 316,793, .dated August, 1919, which is now Patent 1,352,636, dated S ept. 14,1920, I 'provide beneath the two contacts I) b on the under side of the contact plate a two hollow cytion upon the cell.

' position.

for the reception of. the screw threaded stem of a counter-sunk screw (1 d which is inserted into the contact I) b sfrom the top and before the respective contacts are mounted within the contact plate a. lower end of the cylindrical members 0 and c is provided with a hole of a diameter slightly less than that of the main part of it's bore for the retention of a plug 6 eirespectively. This plug at its upper end is provided with a central hole vfor the reception of the end of a spiral spring f f respectively, the opposite end of which contacts with the lower end'of the counter-sunk The screw d or. d and the plugs e e are procavity at their lower ends, the bore of which is screw threaded for the reception of the electrode terminals 2' 5 respectively. An

elongated hole is k is advantageously provided at the upper end of the contacts h k by means of which they may be rotated for being screwed-upon the electrode terminals.

The electrodes are carried uponthe cover plate Z of the cell and at the top near the edge an annular groove is provided for the reception of a screw threaded ring m by means of which the plate is secured in poslecesses m in diametripositions on the ring m serve cally opposite rotating it into or out of the purpose o By such a construction it will be understood that the'spring contacts carried upon the contact plate 6 are not liable to corrosion due to the acid from the cell and that the cell may be re-charged in exactly the same way as other cells except that the contacts of the charging board would be in contact with the flush contacts instead of in contact with the usual spring contacts.

I claim: y

In a miners lamp, in combination, tlgfollowing elements, a contact flate of'insulatm messes ing material, two contacts mounted in said face thereof by means ofcountersunk screws plate and having their respective upper and whose top faces are flush-with the respective lower faces flush with the respective upper faces of the contacts, and spring pressed 10 and lower faces of the contact plate, holplugs at the lower ends of the said cylindri- 5 low cylindrical members internally screw cal members, substantially as described.

threaded at their upper ends for connection l with the respective contacts on the under THEODORE STRETT'ON. 

